Ion-tabs inside ion-content have strange padding top

ionic-v1
1

Hi,
I have this code:

<ion-view title="Attivit&agrave;">
	<ion-nav-buttons side="left">
        <button class="button button-icon button-clear ion-navicon"
            menu-toggle="left"></button>
    </ion-nav-buttons>

    <ion-content>
		<ion-tabs class="tabs-positive tabs-icon-top">

			<ion-tab title="Tutte" icon-on="ion-ios-filing" icon-off="ion-ios-filing-outline">
			</ion-tab>

			<ion-tab title="Vendite" icon-on="ion-ios-clock" icon-off="ion-ios-clock-outline">
			</ion-tab>

			<ion-tab title="B2B E-comm" icon-on="ion-ios-clock" icon-off="ion-ios-clock-outline">
			</ion-tab>

		</ion-tabs>
	</ion-content>
</ion-view>

My problem is that the tabs have a top padding below the toolbar, and I do not know why (see the image).

image